Is WhatsApp too casual for a wedding invitation?
It is how most of your guests already talk. Many couples send a formal card to older relatives and a warm WhatsApp message to friends, with the same link on both. Register is a choice; reach is not, and everyone in the chat sees the invitation at the same time.
Do we still need paper invitations?
Plenty of couples keep a small print run for elders and close family and go digital for the rest. The page works either way: print the link or a QR code on the card and paper guests land on the same reply list as chat guests.
How do I word the plus-one question?
Do not spell out guest-by-guest entitlements in the chat. On the page, each reply shows the plus-one options you actually allowed for that invitation, so the question asks itself inside your limits and nothing awkward has to be typed by anyone.
When should the wedding message go out?
In step with your cards: roughly two to three months before the day for a local wedding, earlier if many guests travel. Save-the-date messages can run a year ahead, which gives the reply deadline room to be generous.
What if someone replies by text instead of tapping?
It happens, and one line back sorts it: lovely, and could you tap the link and confirm there so the numbers count properly. The list updates itself, so the message never has to become your spreadsheet.